Amid the ongoing debate over ethanol-blended E20 petrol, Union Road Transport and Highways Minister Nitin Gadkari has said that motorists cannot accurately determine their vehicle’s fuel efficiency on their own and should instead rely on tests conducted by authorised dealerships.
Speaking in an interview with ABP News, Gadkari responded to a journalist who claimed that her car’s mileage had dropped significantly after switching to E20 petrol.
The journalist said her car, purchased in 2023 and expected to be E20-compatible, was earlier delivering around 11 km per litre in city driving but had recently fallen to about 7 km per litre.
When asked how the mileage was measured, she said it was based on the vehicle’s dashboard fuel economy display.
Gadkari questioned the reliability of such readings, saying that accurate mileage cannot be verified by individual users.
“You and I can’t check the mileage. A car’s mileage can only be checked using a company-authorised dealer’s machine,” the minister said.
Centre Acknowledges Mileage Impact
The remarks come shortly after the Ministry of Petroleum and Natural Gas acknowledged that E20 petrol may reduce fuel economy by 3% to 5% in some vehicles.
However, the ministry defended the Ethanol Blended Petrol (EBP) Programme, stating that fuel economy is only one aspect of vehicle performance and that ethanol blending helps reduce crude oil imports, improve energy security and lower emissions.
The nationwide rollout of E20 petrol became mandatory from April 1.
Can Drivers Check Mileage Themselves?
Automotive experts say that while dashboard fuel economy readings are estimates, they are generally reliable and often remain within 2% to 5% of manual calculations.
The most widely accepted method for estimating real-world mileage is the full-tank method, where drivers refill the fuel tank, reset the trip meter, drive normally, and calculate the distance travelled against the fuel consumed during the next refill.
What Dealer Diagnostic Equipment Does
Manufacturer-authorised diagnostic tools do not directly measure real-world mileage under every driving condition.
Instead, they analyse data from the vehicle’s Engine Control Unit (ECU) to assess the performance of components such as fuel injectors, oxygen sensors, airflow sensors and engine calibration.
These systems help identify mechanical or electronic issues that may affect fuel efficiency but do not replace real-world fuel consumption measurements, which are also influenced by traffic conditions, driving style, tyre pressure, air-conditioning use and vehicle load.
The discussion comes as concerns continue to grow among motorists over E20 petrol, particularly regarding its impact on fuel economy and older vehicles, even as the government maintains that the ethanol-blending programme remains beneficial for India’s long-term energy security and environmental goals.
